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Why did my ALT move after eight weeks on survodutide?

Asked 10 Feb 2026Modified 2 months agoViewed 8k times
15

Stated plainly: ALT · eight weeks · survodutide.

I noticed this today and I have not touched anything since, in case the state is diagnostic.

I have not discarded anything yet, so a test is still possible if that is the recommendation.

How do I distinguish the benign explanation from the one that matters?

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askedcake_collapsed13k2810 Feb 2026
7This should probably be in the site help pages rather than buried in an answer. – unit_math 9 months ago
8Good answer, but the confidence interval in the cited trial is wider than implied. – micron22 23 days ago
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5 Answers

Accepted answer first, then by votes
81

Accepted answer

A single laboratory value is a point on a noisy curve. What you want is a trend across at least three draws under comparable conditions, and "comparable" is doing a lot of work in that sentence.

HbA1c is a weighted average, not a flat one: roughly half the signal comes from the most recent month. That is why a value drawn six weeks after a change already reflects most of the effect, and why a value drawn during rapid haematological turnover reflects something other than glycaemia.

Headline results, principal programmes

TrialAgentnDurationPrimary result
STEP 1Semaglutide 2.4 mg1,96168 wk−14.9 % vs −2.4 % weight
STEP 2Semaglutide 2.4 mg, T2DM1,21068 wk−9.6 % vs −3.4 % weight
SURMOUNT-1Tirzepatide 5/10/15 mg2,53972 wk−15 / −19 / −21 % weight
SURMOUNT-4Tirzepatide, withdrawal67088 wkContinued loss vs substantial regain
SELECTSemaglutide 2.4 mg17,604~40 moMACE HR 0.80 (0.72–0.90)
FLOWSemaglutide 1.0 mg, CKD3,533~3.4 yrRenal composite reduced; stopped early
SURMOUNT-OSATirzepatide, OSA46952 wkAHI reduced with and without PAP

It helps to be literal here: the rodent thyroid C-cell findings that generated the labelled warning appear to be species-specific: rodent C-cells express GLP-1 receptors at high density, human C-cells at very low density, and human calcitonin data across large trial populations has not reproduced the signal. A family history of medullary thyroid carcinoma or MEN2 is nonetheless a genuine contraindication rather than a theoretical one.

The PIONEER programme established oral semaglutide’s efficacy and the constraints on its administration, and the bioavailability figure of roughly one per cent is what drives the fasting and water-volume requirements[1].

I would resist reading a subgroup finding as a result. Subgroups in these trials were not powered, and a striking subgroup in a large trial is the expected consequence of multiplicity.

None of this replaces a clinician who can see the whole picture, and the whole picture is usually where the answer is.

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TM
answered · acceptedtobias_maartens94k2585 Jun 2026
6Two of us worked through this independently and arrived here, so it is at least reproducible. – tri_gly_ala 6 months ago
7Worth adding that the method section is where the answer usually is. – kirsi_lahtinen 7 months ago
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31

This is a question about what the trial was designed to answer, and the honest response is that it was not designed to answer this.

The early fall in estimated glomerular filtration rate on treatment is haemodynamic rather than structural. Reduced intraglomerular pressure lowers the filtration rate acutely and preserves the glomerulus chronically — the same pattern seen with renin-angiotensin blockade and with SGLT2 inhibition. A dip of a few millilitres per minute in the first weeks, followed by a shallower long-term slope, is the desired trajectory, not a warning sign.

To be exact about it, apoB and LDL-C disagree because they measure different things: LDL-C is the cholesterol mass carried in the LDL fraction, ApoB is a count of atherogenic particles. Small dense particles carry less cholesterol each, so a person with many small particles has a concordantly higher ApoB than their LDL-C suggests. When they disagree, ApoB is the better risk marker.

The caveat is the population. Trial participants were screened, monitored and supported; the effect size in an unmonitored setting is not the trial effect size, and it is not obvious in which direction the difference runs.

Convert everything to an absolute effect before you compare two interventions. Relative effects are not comparable across different baseline risks.

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LB
answeredliam_bracken12k1616 Feb 2026
6Worth adding that the method section is where the answer usually is. – vialroom 7 months ago
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25

The hazard ratio is the relative effect. What changes decisions is the absolute effect, and converting between them requires the event rate in the control arm, which is usually in the same table and rarely in the abstract.

Estimated average glucose from HbA1c: eAG in mg/dL = 28.7 × A1c − 46.7, or in mmol/L, 1.59 × A1c − 2.59. An A1c of 6.5 per cent is therefore about 140 mg/dL or 7.8 mmol/L. The relationship is a population regression, so an individual can sit well off the line.

Concretely, absolute risk reduction, worked: if the control-arm event rate is 8.0 per cent over the follow-up period and the hazard ratio is 0.80, the treated rate is approximately 6.4 per cent, the absolute risk reduction is 1.6 percentage points, and the number needed to treat is 1 ÷ 0.016 ≈ 63 over that period. A 20 per cent relative reduction and a number needed to treat of 63 are the same finding stated two ways, and only one of them sounds impressive.

SURMOUNT-1 reported mean weight reductions of approximately 15, 19 and 21 per cent at tirzepatide 5, 10 and 15 mg respectively at 72 weeks[1].

One qualification: a trial that demonstrates an endpoint at a given dose has demonstrated it at that dose. Extrapolating the endpoint down the dose ladder is an assumption, not a finding.

The papers are readable. Read the paper rather than the summary of the paper, especially where the summary is enthusiastic.

edited 8 Mar 2026 by plunger_stop — fixed an arithmetic slip in the third paragraph

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answeredplunger_stop18k2827 Feb 2026
20

Concretely, read the estimand before the effect size. Almost every apparent contradiction between two published figures from the same trial resolves once you notice that one is a trial-product estimand and the other is a treatment-policy estimand.

A fasting lipid panel drawn during rapid weight loss reads oddly for a mechanical reason: mobilised adipose tissue delivers free fatty acids to the liver, and hepatic triglyceride export rises. Triglycerides can transiently increase while the person is doing exactly the right thing. Draw the panel when weight has been stable for a few weeks if you want an interpretable number.

FLOW tested a composite renal endpoint — kidney failure, sustained 50 per cent eGFR decline, or renal or cardiovascular death — in type 2 diabetes with chronic kidney disease, and was stopped early for efficacy[1].

Read the confidence interval, read the estimand, and compute the absolute effect yourself. It takes two minutes and it changes how the result feels.

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DB
answeredDr_Fatima_Belkacem52k13810 Mar 2026
17

Stated carefully, the confidence interval is the informative part. A point estimate with an interval spanning no effect is a different object from the same point estimate with a tight interval, and the abstract presents them identically.

A network meta-analysis can rank agents that were never compared directly, but only under a transitivity assumption — that the trials being linked are similar enough in population, duration and endpoint definition for the indirect comparison to hold. In this field that assumption is often visibly violated, which is why indirect rankings should be read as hypotheses.

SELECT reported a hazard ratio of 0.80 (95% CI 0.72–0.90) for the primary composite major adverse cardiovascular event endpoint with semaglutide 2.4 mg in overweight or obese adults with established cardiovascular disease and without diabetes[1].

If the trend across three draws is flat, the difference between draws one and two was noise. Most of what people react to is noise.

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AM
answeredaine_mulcahy35k3822 Apr 2026
4I would gently push back on the second point — the evidence there is thinner than stated. – Dr_Ingrid_Baumgartner 4 months ago
5Adding for future readers: the certificate should carry the lot number, not just a batch code. – Dr_Marek_Zielinski 6 months ago
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Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.

Not medical advice. Research-use-only compounds are not approved for human use.