Decoupled from what? If you are thinking of Pure Shift NMR then be aware that most pure shift experiments provide lower sensitivity than the regular spectra.

Decoupled from other neighbor protons, so that all signal are singlets.

This is pure shift NMR. See this and references cited there: https://www.nmr.chemistry.manchester.ac.uk/?q=node/24

Depending on the pure shift method you can loose up to 90% of signal intensity.

I see three main "easier" strategies to increase the sensitivity of STD.

- Play with the Ligand/Protein ratio (usually from 20:1 up to 100:1);

- Play with the time of the "saturation pulse" (called P42 on Topspin) - the default is usually 50 ms but you can decrease it to up to 5 ms to gain sensitivity. If you decrease it, then you must be aware that the pulse will be less selective and therefore it is better to set the on-resonance frequency to around -0.5 or even -1 ppm;

- If none of these works well, you can always conduct the experiment in deuterated buffer. This, despite being considerably more expensive, increases the sensitivity.

Wish you the best luck.

Thank you @João Neves this is really helpful.