Study analysis · Medicine · 2023
Weekly growth hormone shots may improve liver enzymes and insulin resistance in adults—but this tiny 11-person study can't prove it.
In 11 adults with growth hormone deficiency, switching from daily to weekly shots was linked to small improvements in weight, blood sugar, and liver tests over 6 months—but without a comparison group, we can't know if the switch caused them.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study looked at 11 people before and after they switched to a new weekly hormone shot. Because there was no comparison group, we can't say the new shot caused the improvements—other things could have changed. It only shows a possible link, not proof.
What’s the bottom line?
Doctors switched 11 adults with growth hormone deficiency from daily shots to a weekly shot called somapacitan and followed their health for 6 months.
How strong is this study?
The study is very small and has no control group, so it's like trying a new recipe on 11 friends and asking if they feel better. They might feel better for many reasons. So we should be cautious and not trust the results too much until bigger, better studies are done.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
14 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control groupno control group
- Sample size (n=11)+1.1/20
- Follow-up+10/10
100 / 100
23 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 531 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
This design cannot establish causation — the findings describe an association, not a cause. No control group, no randomization, very small sample (n=11), and unadjusted observational design. Improvements could be due to regression to the mean, natural variation, placebo effect, or other uncontrolled factors. Cannot infer that switching to somapacitan caused the observed changes.
COI Unknown
Could not determine conflict of interest status
No conflict of interest or funding statement was provided; the study evaluates a proprietary long-acting growth hormone (somapacitan), but no industry ties or funding are disclosed.
The manuscript lacks a COI/funding disclosure. It is a small real-world pilot (n=11) from university hospitals; no author affiliations or sponsor roles are stated. The conclusion favors weekly somapacitan, but without disclosure, bias risk cannot be fully assessed.
Key takeaways
- 01
After 6 months, average BMI fell by 0.6 kg/m² (26.7 to 26.1), HOMA-IR fell by 0.8 (3.1 to 2.3), fasting glucose fell by 5.2 mg/dL (104.5 to 99.3), and liver enzymes fell: AST by 3.6 U/L, ALT by 4.6 U/L, and γ-GTP by 4.4 U/L.
- 02
These are absolute within-group changes.
- 03
IGF-1 stayed similar (100.2 to 98.3 ng/mL).
- 04
The improvements are absolute changes in the same 11 people, but without a control group we cannot know whether the weekly shot caused them.
- 05
The absolute risk or benefit compared with staying on daily shots was not reported in this study.
- 06
This was a small pilot, so the results are uncertain.
Surprising findings
- Liver enzymes improved significantly, even though phase 3 trials of somapacitan did not analyze liver functions.This is a new signal not previously reported in the drug's phase 3 program, making it both intriguing and in need of replication.
- The improvement in insulin resistance was linked to how long patients had been on daily growth hormone before switching.It hints that daily growth hormone might be less efficient for glucose metabolism over time, but the finding comes from a tiny uncontrolled pilot.
- IGF-1 levels were virtually identical after switching to weekly somapacitan.A once-weekly shot maintained the same IGF-1 target as daily injections, which supports the idea that the metabolic changes are not explained by differences in IGF-1 exposure.
- Switching to weekly somapacitan did not disrupt other pituitary hormones.Growth hormone can interact with cortisol metabolism, so some change might have been expected—but none was seen in this small study.
Practical takeaways
If you or someone you know uses daily growth hormone injections, talk to an endocrinologist before switching to a weekly formulation like somapacitan.
This study is an uncontrolled pilot of 11 people with no effect sizes or confidence intervals, so it cannot prove that switching improves health outcomes.
low confidenceAfter any switch in growth hormone therapy, ask your doctor to monitor IGF-1 levels and metabolic/liver blood tests.
Monitoring is reasonable, but this study does not show that routine monitoring improves outcomes; it only observed changes in a small group.
medium confidenceDo not interpret the improvements as proof that weekly growth hormone is superior to daily growth hormone.
Without a control group, the absolute improvements could be due to chance, regression to the mean, or other factors.
high confidenceWhen reading health headlines about small pilot studies, look for the words 'no control group' and 'small sample size' before changing your beliefs.
This is a general critical-thinking tip, not medical advice.
high confidenceWhy this study matters
Tiny study, big caveat: no control group
Eleven adults with adult growth hormone deficiency switched from daily growth hormone replacement to once-weekly somapacitan. After 6 months, researchers saw absolute within-group improvements in BMI, insulin resistance, fasting glucose, and liver enzymes. But there was no control group, so these changes cannot be attributed to somapacitan—they could reflect regression to the mean, natural variation, or other factors.
It is a textbook example of why before-and-after studies can't prove cause and effect. The headline-friendly improvements may not be caused by the drug switch at all.
Metabolic improvements: small absolute drops in BMI, HOMA-IR, and fasting glucose
BMI decreased by an absolute 0.6 kg/m² (26.7 to 26.1, P=0.007). HOMA-IR, a measure of insulin resistance, dropped by an absolute 0.8 (3.1 to 2.3, P=0.022). Fasting plasma glucose fell by an absolute 5.2 mg/dL (104.5 to 99.3, P=0.044). No relative risk or effect sizes with confidence intervals were reported.
Insulin resistance and blood sugar are major health concerns. Even small absolute improvements sound promising—but without a control group, we can't know if they are real treatment effects.
Liver enzymes dropped across the board
All three measured liver enzymes improved in absolute terms over 6 months: AST fell from 23.4 to 19.8 U/L (P=0.001), ALT from 19.6 to 15.0 U/L (P=0.004), and γ-GTP from 25.2 to 20.8 U/L (P=0.018). The authors note that phase 3 trials of somapacitan did not analyze liver functions, making this a new signal—but still uncontrolled.
Liver health is a hot topic, and fatty liver disease is common in adult growth hormone deficiency. A weekly shot improving liver enzymes would be a big deal if proven.
IGF-1 stayed stable: the weekly shot did its job
The key hormone marker IGF-1 was essentially unchanged after switching: 100.2 ng/mL at baseline versus 98.3 ng/mL after 6 months (P=0.316). All patients stayed within the target range (-1 to +1 SDS), suggesting the weekly dose was titrated to match prior daily therapy.
It suggests the switch maintained the hormone's core effect, so any metabolic changes are not simply due to lower or higher IGF-1 exposure.
Other endocrine hormones didn't budge
ACTH, cortisol, TSH, free T4, LH, FSH, and testosterone/estradiol remained stable over 6 months. The authors conclude that switching 'did not affect endocrinological parameters.' This is reassuring for safety, though the tiny sample limits precision.
People worry that changing hormone regimens could disrupt the whole endocrine system. This pilot found no such disruption.
Longer prior daily therapy linked to bigger insulin-resistance improvement
In a univariate analysis, the improvement in HOMA-IR was positively associated with the duration of prior daily growth hormone therapy (P=0.048). Age, sex, BMI improvement, liver function improvement, hormonal deficiencies, and other hormone replacement therapies were not significantly associated. This does not prove causation and could reflect confounding.
If real, it would suggest that patients on daily shots for longer might benefit more from switching—but with only 11 people, this could easily be a chance finding.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Doctors switched 11 adults with growth hormone deficiency from daily shots to a weekly shot called somapacitan and followed their health for 6 months.
Research results
After 6 months, average BMI fell by 0.6 kg/m² (26.7 to 26.1), HOMA-IR fell by 0.8 (3.1 to 2.3), fasting glucose fell by 5.2 mg/dL (104.5 to 99.3), and liver enzymes fell: AST by 3.6 U/L, ALT by 4.6 U/L, and γ-GTP by 4.4 U/L. These are absolute within-group changes. IGF-1 stayed similar (100.2 to 98.3 ng/mL).
What this means - more context
The improvements are absolute changes in the same 11 people, but without a control group we cannot know whether the weekly shot caused them. The absolute risk or benefit compared with staying on daily shots was not reported in this study. This was a small pilot, so the results are uncertain.
To evaluate metabolic and endocrinological effects of switching adults with growth hormone deficiency from daily GH replacement to once-weekly somapacitan in a real-world pilot.
In 11 adults with AGHD, 6 months after switching to weekly somapacitan, absolute within-group improvements occurred in BMI (26.7 to 26.1 kg/m²), HOMA-IR (3.1 to 2.3), fasting plasma glucose (104.5 to 99.3 mg/dL), and liver enzymes (AST 23.4 to 19.8 U/L; ALT 19.6 to 15.0 U/L; γ-GTP 25.2 to 20.8 U/L). IGF-1 and endocrinological parameters remained stable. Because there was no control group, these changes cannot be attributed to somapacitan.
Methods Used
Uncontrolled pre-post pilot of 11 adults with AGHD who had received daily GH replacement for over 2 years and switched to weekly somapacitan; dose titrated to maintain IGF-1 within target range; metabolic and endocrinological parameters measured at switching and 6 months later. No control group.
Main Finding
Switching to weekly somapacitan was associated with significant absolute within-group improvements over 6 months: BMI decreased by 0.6 kg/m² (26.7 to 26.1, P=0.007), HOMA-IR by 0.8 (3.1 to 2.3, P=0.022), fasting plasma glucose by 5.2 mg/dL (104.5 to 99.3, P=0.044), AST by 3.6 U/L (23.4 to 19.8, P=0.001), ALT by 4.6 U/L (19.6 to 15.0, P=0.004), and γ-GTP by 4.4 U/L (25.2 to 20.8, P=0.018). IGF-1 was unchanged (100.2 vs 98.3 ng/mL, P=0.316), and anterior pituitary-related hormones remained stable. Without a control group, causality cannot be established.
Confidence Level
Low: very small single-arm pilot (n=11), no control group, short 6-month follow-up, and no effect sizes or confidence intervals reported; findings are hypothesis-generating only.
Study Flags
Red Flags
- •No control group
- •Very small sample size (n=11)
- •Short 6-month follow-up
Surprising Findings
Liver enzymes improved significantly, even though phase 3 trials of somapacitan did not analyze liver functions.
This is a new signal not previously reported in the drug's phase 3 program, making it both intriguing and in need of replication.
Practical Takeaways
If you or someone you know uses daily growth hormone injections, talk to an endocrinologist before switching to a weekly formulation like somapacitan.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 531 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Human Cohort Study
Subject
Lower probability
on the GRADE evidence scale
This study looked at 11 people before and after they switched to a new weekly hormone shot. Because there was no comparison group, we can't say the new shot caused the improvements—other things could have changed. It only shows a possible link, not proof.
Strengths
- Prospective follow-up of 6 months
- All other medical treatments remained unchanged
- IGF-1 titration protocol
Weaknesses
- No control group
- Very small sample size (n=11)
- No randomization or blinding
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Doctors switched 11 adults with growth hormone deficiency from daily shots to a weekly shot called somapacitan and followed their health for 6 months.
Research results
After 6 months, average BMI fell by 0.6 kg/m² (26.7 to 26.1), HOMA-IR fell by 0.8 (3.1 to 2.3), fasting glucose fell by 5.2 mg/dL (104.5 to 99.3), and liver enzymes fell: AST by 3.6 U/L, ALT by 4.6 U/L, and γ-GTP by 4.4 U/L. These are absolute within-group changes. IGF-1 stayed similar (100.2 to 98.3 ng/mL).
What this means - more context
The improvements are absolute changes in the same 11 people, but without a control group we cannot know whether the weekly shot caused them. The absolute risk or benefit compared with staying on daily shots was not reported in this study. This was a small pilot, so the results are uncertain.
To evaluate metabolic and endocrinological effects of switching adults with growth hormone deficiency from daily GH replacement to once-weekly somapacitan in a real-world pilot.
In 11 adults with AGHD, 6 months after switching to weekly somapacitan, absolute within-group improvements occurred in BMI (26.7 to 26.1 kg/m²), HOMA-IR (3.1 to 2.3), fasting plasma glucose (104.5 to 99.3 mg/dL), and liver enzymes (AST 23.4 to 19.8 U/L; ALT 19.6 to 15.0 U/L; γ-GTP 25.2 to 20.8 U/L). IGF-1 and endocrinological parameters remained stable. Because there was no control group, these changes cannot be attributed to somapacitan.
Methods Used
Uncontrolled pre-post pilot of 11 adults with AGHD who had received daily GH replacement for over 2 years and switched to weekly somapacitan; dose titrated to maintain IGF-1 within target range; metabolic and endocrinological parameters measured at switching and 6 months later. No control group.
Main Finding
Switching to weekly somapacitan was associated with significant absolute within-group improvements over 6 months: BMI decreased by 0.6 kg/m² (26.7 to 26.1, P=0.007), HOMA-IR by 0.8 (3.1 to 2.3, P=0.022), fasting plasma glucose by 5.2 mg/dL (104.5 to 99.3, P=0.044), AST by 3.6 U/L (23.4 to 19.8, P=0.001), ALT by 4.6 U/L (19.6 to 15.0, P=0.004), and γ-GTP by 4.4 U/L (25.2 to 20.8, P=0.018). IGF-1 was unchanged (100.2 vs 98.3 ng/mL, P=0.316), and anterior pituitary-related hormones remained stable. Without a control group, causality cannot be established.
Confidence Level
Low: very small single-arm pilot (n=11), no control group, short 6-month follow-up, and no effect sizes or confidence intervals reported; findings are hypothesis-generating only.
Study Flags
Red Flags
- •No control group
- •Very small sample size (n=11)
- •Short 6-month follow-up
Surprising Findings
Liver enzymes improved significantly, even though phase 3 trials of somapacitan did not analyze liver functions.
This is a new signal not previously reported in the drug's phase 3 program, making it both intriguing and in need of replication.
Practical Takeaways
If you or someone you know uses daily growth hormone injections, talk to an endocrinologist before switching to a weekly formulation like somapacitan.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 531 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Human Cohort Study
Subject
Lower probability
on the GRADE evidence scale
This study looked at 11 people before and after they switched to a new weekly hormone shot. Because there was no comparison group, we can't say the new shot caused the improvements—other things could have changed. It only shows a possible link, not proof.
Strengths
- Prospective follow-up of 6 months
- All other medical treatments remained unchanged
- IGF-1 titration protocol
Weaknesses
- No control group
- Very small sample size (n=11)
- No randomization or blinding
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The study is very small and has no control group, so it's like trying a new recipe on 11 friends and asking if they feel better. They might feel better for many reasons. So we should be cautious and not trust the results too much until bigger, better studies are done.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
14 / 100
- Randomizationnot randomized
- Blindingblinding unclear
- Control groupno control group
- Sample size (n=11)+1.1/20
- Follow-up+10/10
100 / 100
23 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 531 / 100
Probability of being correct
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
This design cannot establish causation — the findings describe an association, not a cause. No control group, no randomization, very small sample (n=11), and unadjusted observational design. Improvements could be due to regression to the mean, natural variation, placebo effect, or other uncontrolled factors. Cannot infer that switching to somapacitan caused the observed changes.
COI Unknown
Could not determine conflict of interest status
No conflict of interest or funding statement was provided; the study evaluates a proprietary long-acting growth hormone (somapacitan), but no industry ties or funding are disclosed.
The manuscript lacks a COI/funding disclosure. It is a small real-world pilot (n=11) from university hospitals; no author affiliations or sponsor roles are stated. The conclusion favors weekly somapacitan, but without disclosure, bias risk cannot be fully assessed.
Standing
The people behind it
The researchers who wrote the study this analysis is built on.
Authored by
11 researchersIf this is your work, this is how we attribute it on Fit Body Science. Ichiro Abe is listed as the lead author.
- Kaori TakeshitaCorresponding