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[Why an average leaves questions](/#why-an-average-is-incomplete) · [How we read a reported range](/reading-ranges) · [What the human results can tell us](/human-results)

[SD Peptides](/) / Follow a sentence back to its source

# Follow the finding back to the source.

A link is useful when it helps answer the question you’re reading about. Here are the sources cited across SD Peptides, with a note on what each adds and where its answer stops.

## Human results and what happened later

### [Semaglutide in adults with overweight or obesity](https://pubmed.ncbi.nlm.nih.gov/33567185/)

A human trial with a dummy treatment for comparison. We use the average weight change and the share reaching a goal; neither tells everyone’s story.

### [Weight regain after semaglutide withdrawal](https://pubmed.ncbi.nlm.nih.gov/35441470/)

A smaller group followed after the medicine and lifestyle support stopped. The regain figure describes people previously taking semaglutide; it does not decide a person’s treatment length.

### [Semaglutide prescribing information](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ee06186f-2aa3-4990-a760-757579d8f77b)

The safety warnings include tumours in thyroid C cells seen in rodents. Whether that happens in humans is unknown; both parts belong in the explanation.

## Healing claims and the exact substance

### [FDA review of BPC-157](https://www.fda.gov/media/193343/download)

The FDA separates small human reports from animal work. Those human studies can’t establish safety, even when their reports sound reassuring.

### [BPC-157 and a cut Achilles tendon in rats](https://pubmed.ncbi.nlm.nih.gov/14554208/)

An experiment on cut tendons in rats. It doesn’t tell us when a person with an everyday injury will move comfortably again.

### [FDA review of TB-500](https://www.fda.gov/media/193349/download)

The review found no published human TB-500 studies. It also explains why TB-500 can’t borrow findings about full-length thymosin beta-4.

## Cells, skin and mice

### [GHK-Cu and collagen production in cell cultures](https://pubmed.ncbi.nlm.nih.gov/3169264/)

A finding about collagen production in skin cells grown in a dish. That isn’t a measured change in someone’s skin.

### [Copper tripeptide on skin after laser resurfacing](https://pubmed.ncbi.nlm.nih.gov/16847171/)

After laser treatment, the GHK-Cu group reported more satisfaction. The measured skin outcomes did not establish a statistically clear benefit; the small headcount leaves room for uncertainty.

### [MOTS-c in cells and mice](https://pubmed.ncbi.nlm.nih.gov/25738459/)

Mice gained less weight on a high-fat diet and handled sugar better. The study doesn’t give us a human weight-loss result.

### [FDA review of MOTS-c](https://www.fda.gov/media/193347/download)

The FDA found no human data to establish benefit or safety. An explanation of how MOTS-c might work can’t replace those missing results.

### [KPV uptake and intestinal inflammation](https://pubmed.ncbi.nlm.nih.gov/18061177/)

Work on cells and bowel inflammation caused in mice. The mouse finding leaves the question about human bowel disease unanswered.

### [FDA review of KPV](https://www.fda.gov/media/193346/download)

The FDA found no human studies of KPV. Side effects remain unknown; possible immune reactions aren’t measured harms in people.

## Approval and safety context

### [FDA safety concerns and withdrawn nominations](https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks)

The page current as of April 22, 2026 lists withdrawn nominations alongside safety concerns. Withdrawal means no approval or clearance, and it gives no individual move dates.

### [FDA explanation of compounded drug risks](https://www.fda.gov/drugs/human-drug-compounding/understanding-risks-compounded-drugs)

A compounded medicine is prepared for a particular patient’s medical needs. Those medicines aren’t FDA-approved, even when an approved medicine contains the same ingredient.

## Read the link with its sentence

We check whether the people or animals, substance and outcome match the claim. A paper on a related substance isn’t a substitute. If the source leaves the answer open, the sentence needs to leave it open too.

Return to [the opening examples](/) or [our page on ranges](/reading-ranges) to put those questions to work. The teaching examples add no results to these studies.


We explain the room around a result; this is a research guide, not a clinic, pharmacy or seller.

© 2026 SD Peptides

[What the human results can tell us](/human-results)

[The missing steps in healing claims](/repair-claims)

[The distance from a cell to a person](/cell-to-person)

[How we read a reported range](/reading-ranges)

[Follow a sentence back to its source](/references)

[Why we make room around the average](/about)

[What a research question can ask here](/contact)