From a Jain dharma perspective:

• Algae-based supplements (like spirulina or chlorella) are generally acceptable. They come from microalgae, not animals, and don’t involve harming sentient beings in the same way as animal products. This aligns with ahimsa (non-violence).
• The key is how the product is produced and consumed. Ensure it is truly vegan/vegetarian (no gelatin capsules, no animal-derived additives, and no processing that involves harming living beings unnecessarily).
• Be mindful of the broader Jain principle of not harming life more than necessary. Some people follow stricter views about which life forms may be harmed in cultivation or harvesting; algae are simple organisms, but keep an eye on sustainable, low-impact farming.

Practical tips for choosing:

• Check capsule or tablet ingredients: look for vegan capsules or tablets without animal-derived materials.
• Read labels for additives: avoid dairy, honey, or other non-vegetarian components.
• Prefer products from transparent, sustainable sources with minimal processing that avoids unnecessary harm.
• If you are observing special fasting or discipline (upvas, long austerities), consult a knowledgeable Jain teacher or elder about whether to include supplements in your regimen.

If you’d like, I can help find a Jain-friendly explanation or related guidance on JainKnowledge.com.