The user's cells and body tissue are more powerful than the average human being's, the cells and tissues have increased at supernatural levels which access the entire body and just about anything connected to cells, their entire body are modified and enhanced at the cellular or genetic levels, granting superhuman capabilities and have full control of them.
There are at least over 75 trillion cells in the human body and are more than 200 different types cells and body tissues that each work on a particular functions, that form the human body, including brain cells and tissues, muscle tissue, blood cells, stem cells, nerve cells, hormones, etc, are at their most powerful capacity.
Saiyans such as Goku (Dragon Ball) can assume the different Super Saiyan forms due to the presence of S-Cells within their bodies; the more S-Cells a Saiyan possesses, the easier it is for them to transform.
Jenova's (Final Fantasy VII) cells grant those infused with them superhuman abilities.
Shu Ouma (Guilty Crown) is a carrier of the Void Genome.
After a bag of the CPH4 accidentally broke inside Lucy (Lucy) her cells augmented to supernatural levels.
The Hulk's (Marvel Comics) gamma induces cells expand in great rage making him that much stronger.
Hashirama Senju's (Naruto) Wood Release techniques are so unique to himself that only those who have artificially implanted themselves with his cells can use them.
Mitochondria Eve (Parasite Eve) possesses supernaturally active mitochondria in her cells that grant her superhuman abilities...
...as does Aya Brea during a corneal transplant.
Alex Mercer (Prototype) gained his powers by a lethal virus that mutated his cells.
James Heller (Prototype 2) gained the same cellular powers as Alex Mercer.
A ghoul's kagune (Tokyo Ghoul) is entirely composed of Rc cells.
Toriko (Toriko) was naturally born with Gourmet Cells.
The Cells of Species 8472 (Star Trek Voyager) are the most densely packed cell structure that exists, as such they are immune to and can destroy anything that penetrates their cells- chemical, biological or technological.
The symbol of the Devil Gene (Tekken)
Gourmet Cells (Toriko) in both injection and pill form.
The Corvinus Strain (Underworld) is the parent strain for both the Vampire and Lycan viruses, and can also sustain and combine the two.
Regen Serum (Marvel Comics)
The X-Gene (Marvel Comics), the source of all mutants' powers.