Semaglutide with B12 is a compounded injection. A pharmacy mixes semaglutide and vitamin B12 in one vial. Wegovy, the approved injection, contains none.[3]
The price question comes first. The whole compounded market is below. The compounded semaglutide cost guide breaks it down.
$184
Typical compounded semaglutide injection month (380 sellers)
$76 to $485
Range of published compounded months
14
Priced sellers whose listing mentions B12, of 380
Those figures cover every priced compounded injection, with and without B12. They were read through September 2026.
Does B12 change the price?
Sometimes. Some sellers list a B12 version beside a plain one at a different price. Others sell only the B12 mix.
This site’s price records note B12 in free text, not as a field. So the count above is a floor. No B12-only median is printed, because it would not be a real market.
The rule for comparing is simple. Price a B12 mix against another B12 mix. Price plain against plain.
What Wegovy contains
The Wegovy pen holds semaglutide in water with a phosphate buffer and salt[3]. No vitamin is listed[3]. So B12 is not part of the approved drug.
Why a pharmacy adds it
B12 is an approved drug in its own right. Injectable cyanocobalamin is labeled for B12 deficiency from malabsorption[2]. It is given into muscle or under the skin[2].
The FDA pages cited here give no clinical reason to add it to semaglutide. Sellers give their own reasons. Treat those as marketing, not evidence.
The mix is common. A 2025 secret-shopper study covered 75 clinics and medical spas[4]. Of those, 42 (56.0%) offered GLP-1 drugs combined with B vitamins[4]. The study covered West Virginia and Oklahoma[4].
What FDA says about the mix
A 503A pharmacy may not regularly compound copies of commercially available drugs[1]. FDA’s April 2026 update uses semaglutide with B12 as its example[1].
FDA may treat the mix as a copy of two approved drugs[1]. That applies when it is injected like them[1]. It also applies when each strength is within 10% of an approved product[1].
There are two exceptions. A prescriber can document a significant difference for one patient[1]. And FDA does not intend to act at four or fewer such prescriptions a month[1]. The pharmacy tiers are in 503A vs 503B.
Four questions before paying
- Is the quoted price for the B12 mix or for plain semaglutide?
- How much B12 is in each dose?
- Which pharmacy compounds it, and is it 503A or 503B?
- Does the price rise with the semaglutide dose?
Whether any generic exists is covered in generic semaglutide. The brand’s price is in the Wegovy cost guide. Reviewed sellers are on the reviews page.