[8] Each individual B vitamin is water-soluble and generally very safe at physiologic doses, but the combination product should only be used when clearly needed
In addition, if you have combination to oily skin type, use the serum or liquid versions
Start with the beginner protocol (5 mg/week) and assess for two weeks

NAD+ vs NMN vs NR (and IV vs SubQ) NAD+ Delivery Comparison Feature Mechanism NAD+ Injection (SubQ) Direct coenzyme delivery NAD+ Infusion (IV) Direct coenzyme delivery Oral NMN NAD+ precursor (converted in vivo) Oral NR (Niagen) NAD+ precursor (converted in vivo) Feature Typical research-planning dose NAD+ Injection (SubQ) 50-100 mg, 2-3x/week NAD+ Infusion (IV) 250-1,000 mg per session Oral NMN 300-600 mg/day Oral NR (Niagen) 300-1,000 mg/day Feature Speed to systemic NAD+ rise NAD+ Injection (SubQ) Hours NAD+ Infusion (IV) Minutes to hours Oral NMN Days to weeks Oral NR (Niagen) Days to weeks Feature Strongest human evidence NAD+ Injection (SubQ) Limited NAD+ Infusion (IV) Pilot PK and historical case reports Oral NMN Growing RCT base Oral NR (Niagen) Strongest RCT base Feature Convenience NAD+ Injection (SubQ) At-home injection technique required NAD+ Infusion (IV) Clinic visit, 2-4 hour infusion Oral NMN Daily oral capsule Oral NR (Niagen) Daily oral capsule Feature Regulatory status NAD+ Injection (SubQ) Not FDA-approved

Conditions such as Crohns, coeliac disease or previous gut surgery, and the autoimmune cause behind pernicious anaemia, all affect how well you retain B12
Or let it dissolve passively in the refrigerator