Should You Take Semaglutide with Vitamin B12?

There is limited direct scientific proof connecting semaglutide use to vitamin B12 deficiency, and no consensus recommending routine B12 supplementation for people taking semaglutide.

Semaglutide is the active compound in Ozempic and Rybelsus and is prescribed for managing type 2 diabetes and for weight loss in people with obesity.

Do clinicians advise taking B12 alongside semaglutide?

Compounded formulations that combine semaglutide with vitamin B12 are available commercially but have not been approved by the U.S. Food and Drug Administration (FDA). Some clinicians suggest the pairing based on theoretical grounds rather than definitive clinical evidence.

Semaglutide acts by imitating GLP-1, a gut hormone that helps regulate blood glucose by promoting insulin release, lowering glucagon secretion, and slowing gastric emptying.

All GLP-1 receptor agonists, including semaglutide, delay stomach emptying and can reduce gastric acid secretion. These effects may influence the absorption of vitamin B12, potentially contributing to deficiency or worsening an existing deficiency. Vitamin B12 requires adequate stomach acid and intrinsic factor — a protein produced by the stomach — for proper absorption.

In theory, a compounded semaglutide-plus-B12 injection could help prevent B12 deficiency and might even augment the medication’s overall benefits.

That said, there’s no robust evidence that semaglutide must be taken together with vitamin B12. It’s best to speak with a healthcare provider to determine whether B12 supplementation is appropriate based on your individual risk factors and needs.

Could semaglutide combined with B12 increase weight loss?

Semaglutide has demonstrated effectiveness for weight reduction in people with obesity.

In a clinical study, semaglutide administered over 104 weeks produced substantial weight loss for individuals with overweight or obesity and related conditions. Participants on semaglutide lost an average of 15.2% of their body weight versus 2.6% in the placebo group, though gastrointestinal adverse effects were more common with semaglutide.

While B12 is not typically prescribed as a standalone weight-loss medication, it plays an important role in overall health and may support metabolism and cellular energy production, which could theoretically complement semaglutide’s weight-loss effects. More research is necessary to establish whether compounded semaglutide with vitamin B12 provides additional weight-loss benefit.

What to expect from a semaglutide plus B12 injection

A compounded semaglutide and B12 injection is generally given as a subcutaneous shot (under the skin). Below are common expectations for semaglutide therapy:

• Injection site: The shot is typically administered in the abdomen, thigh, or upper arm. A clinician will instruct you on proper injection technique or administer it for you.
• Frequency: Semaglutide with B12 is usually administered once weekly. Initiation often begins with a 0.25 mg dose, and your prescriber may increase to 0.5 mg depending on tolerance and therapeutic goals.
• Weight loss: In a study of 175 adults with overweight or obesity, semaglutide users lost about 5.9% of body weight at 3 months and 10.9% at 6 months. For someone weighing 200 pounds, that equates to roughly 11–21 pounds at 3 months and 20–39 pounds at 6 months. Some propose that adding B12 could enhance these outcomes.
• Improved glycemic control: Semaglutide enhances insulin secretion and lowers hepatic glucose production, helping reduce blood sugar. B12 may support pancreatic cell health, which could indirectly aid glucose regulation.
• Higher energy: Vitamin B12 can help counteract fatigue sometimes reported during semaglutide therapy, potentially improving energy and overall well-being.
• Cardiovascular support: B12 contributes to markers of cardiovascular health, which may reduce certain heart-related risks in people with type 2 diabetes.
• Addressing adverse effects: Although semaglutide’s side effects are often mild (nausea, diarrhea), research is exploring whether B12 added to the compound might reduce some gastrointestinal symptoms.

Possible adverse effects

Semaglutide commonly causes gastrointestinal issues such as nausea, diarrhea, or constipation. These symptoms are usually mild and tend to diminish over time.

Some individuals may experience increased appetite or hunger if they miss a scheduled dose of semaglutide.

Bottom line

Semaglutide is used to treat type 2 diabetes and obesity by imitating the hormone GLP-1, which helps manage blood glucose and curb appetite. Combining semaglutide with vitamin B12 might theoretically boost its effects, since B12 supports energy and nervous system function. However, this idea remains speculative and is not backed by definitive scientific evidence.

If you believe you could benefit from a compounded semaglutide and vitamin B12 regimen, discuss the potential advantages and risks with your healthcare provider before starting treatment.

For related information, you may find these resources helpful: ozempic and other glp 1 drugs may make surgery more dangerous study finds, tirzepatide vs semaglutide, and semaglutide food list.